The investigation stems from a recent incident with a child on board a private plane flying from Europe to Los Angeles, the source said. The incident was anonymously reported to authorities several days later. Pitt has six children with actress Angelina Jolie, who filed for divorce from the actor on Monday.

The Los Angeles Police Department and the FBI have not launched an investigation. An FBI spokeswoman, Laura Eimiller, said in a statement late Thursday that the agency is still evaluating whether to do its own investigation into the allegations.

Citing irreconcilable differences, Jolie filed for divorce "for the health of the family," her lawyer Robert Offer told The Associated Press. Jolie is asking for physical custody of their six children — Maddox, 15, Pax, 12, Zahara, 11, Shiloh, 10, and twins Vivienne and Knox, 8. The couple married on August 14, 2014 after a 12-year relationship.

"Angelina will always do what’s in the best interest to protect her children," her manager Geyer Kosinski told E! News in a statement. "She appreciates everyone's understanding of their need for privacy at this time."

In a statement released to People Magazine, Pitt said his focus is also on the "well-being of our kids," adding that he is saddened by divorce and asking "the press to give [the children] the space they deserve during this challenging time."

Pitt was previously married to actress Jennifer Aniston in 2000, divorcing in 2005. This was the third marriage for Jolie, having previously been wed to Jonny Lee Miller in 1996 and Billy Bob Thornton in 2000.